File size: 3,949 Bytes
fea99b3
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
package datetime

import (
	"encoding/json"
	"time"

	"github.com/alpacahq/alpacadecimal"
)

// DateTime extends the time.Time type to support the RFC 9557 format.
type DateTime struct {
	time.Time
}

// NewDateTime creates a new DateTime from a time.Time.
func NewDateTime(t time.Time) DateTime {
	return DateTime{t}
}

// AsTime returns the underlying time.Time.
func (t DateTime) AsTime() time.Time {
	return t.Time
}

// MarshalJSON marshals the DateTime to a JSON string in RFC3339 format.
func (t DateTime) MarshalJSON() ([]byte, error) {
	return json.Marshal(t.Format(time.RFC3339))
}

// UnmarshalJSON unmarshals the DateTime from a JSON string.
// It supports RFC3339, ISO8601, and RFC9557 formats.
func (t *DateTime) UnmarshalJSON(data []byte) error {
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return err
	}

	date, err := Parse(s)
	if err != nil {
		return err
	}

	*t = date

	return nil
}

// Add adds a duration to a DateTime.
func (dt DateTime) Add(d ISODuration) DateTime {
	years := d.Years()
	months := d.Months()
	weeks := d.Weeks()
	days := d.Days()
	hours := d.Hours()
	minutes := d.Minutes()
	// We can safely ignore this error
	seconds, _ := alpacadecimal.NewFromString(d.SecondsDecimal().String())

	dt = dt.AddYearsNoOverflow(years).
		AddMonthsNoOverflow(months).
		AddWeeks(weeks).
		AddDays(days).
		AddHours(hours).
		AddMinutes(minutes).
		AddSeconds(seconds)

	return dt
}

// AddDateNoOverflow adds some years, months, and days without overflowing month.
func (d DateTime) AddDateNoOverflow(years int, months int, days int) DateTime {
	d = d.AddYearsNoOverflow(years).
		AddMonthsNoOverflow(months).
		AddDays(days)

	return d
}

// AddYearsNoOverflow adds some years without overflowing month.
func (d DateTime) AddYearsNoOverflow(years int) DateTime {
	nanosecond := d.Nanosecond()
	year, month, day := d.Date()
	hour, minute, second := d.Clock()
	// get the last day of this month after some years
	lastYear, lastMonth, lastDay := time.Date(year+years, month+1, 0, hour, minute, second, nanosecond, d.Location()).Date()
	if day > lastDay {
		day = lastDay
	}
	return d.shiftClockTo(time.Date(lastYear, lastMonth, day, hour, minute, second, nanosecond, d.Location()))
}

// AddMonthsNoOverflow adds some months without overflowing month.
func (d DateTime) AddMonthsNoOverflow(months int) DateTime {
	nanosecond := d.Nanosecond()
	year, month, day := d.Date()
	hour, minute, second := d.Clock()
	// get the last day of this month after some months
	lastYear, lastMonth, lastDay := time.Date(year, month+time.Month(months+1), 0, hour, minute, second, nanosecond, d.Location()).Date()
	if day > lastDay {
		day = lastDay
	}
	return d.shiftClockTo(time.Date(lastYear, lastMonth, day, hour, minute, second, nanosecond, d.Location()))
}

// AddWeeks adds some weeks to the DateTime.
func (d DateTime) AddWeeks(weeks int) DateTime {
	return d.shiftClockTo(d.Time.AddDate(0, 0, weeks*7))
}

// AddDays adds some days to the DateTime.
func (d DateTime) AddDays(days int) DateTime {
	return d.shiftClockTo(d.Time.AddDate(0, 0, days))
}

// AddHours adds some hours to the DateTime.
func (d DateTime) AddHours(hours int) DateTime {
	return d.shiftClockTo(d.Time.Add(time.Duration(hours) * time.Hour))
}

// AddMinutes adds some minutes to the DateTime.
func (d DateTime) AddMinutes(minutes int) DateTime {
	return d.shiftClockTo(d.Time.Add(time.Duration(minutes) * time.Minute))
}

// AddSeconds adds some seconds to the DateTime.
func (d DateTime) AddSeconds(seconds alpacadecimal.Decimal) DateTime {
	nano := seconds.Mul(alpacadecimal.NewFromInt(int64(time.Second))).BigInt().Int64()
	return d.shiftClockTo(d.Time.Add(time.Duration(nano)))
}

// To mimic time.Add(d time.Duration) behavior, we want to use clock shift instead of constructing time instances.
func (d DateTime) shiftClockTo(t time.Time) DateTime {
	wallTimeDiff := t.Sub(d.Time.Round(0))
	d.Time = d.Time.Add(wallTimeDiff)
	return d
}